A large boulder has been blown up above the A83 at the Rest and Be Thankful.
Engineers from roads maintenance body Bear blasted the 150-tonne rock, which was sitting around 175m above the carriageway, shortly before 5pm on Wednesday.
Poor visibility caused by low cloud had led to the possibility of the operation being delayed until Thursday, but at 4pm the decision was taken to detonate the explosives.
The work saw a series of holes drilled to weaken the rock every half-metre along its face. Explosives were then detonated to break it into smaller pieces.
Netting was placed over the boulder to reduce the scatter of debris and engineers then began the process of breaking up the remnants.
The road had been closed since Tuesday, and an announcement as to when it will reopen is expected later on Wednesday.